S7

Blackwater and blackwater treatment for biogas production

This solution includes two core AD technologies for treatment of blackwater and biowaste at building scale, including the efficient collection and grinding at source.

Solution S7A is based on the joint treatment of blackwater and grinded blackwater at building (pilot) scale for wet anaerobic digestion using AnMBR solution. The solution foresees the recovery of >95% food waste and >95% organic matter from blackwater. This may lead to:

>90% treated blackwater reuse for toilet or fertigation;

renewable energy from biogas (linked to S7c);

compost (linked to S8) at home level for use by dwellers, neighbours or use in public gardens.

In HOUSEFUL, an innovative AnMBR system for the joint treatment of blackwater and grinded BW will be designed and constructed at laboratory and pilot scale as a compact and transportable unit. The design will be addressed for a minor odour production. The systems will be started up and optimised using real wastewater and grinded bio-waste effluents. Biogas will be treated using absorption technologies (Solution S7c) ensuring a biogas quality corresponding to natural gas grid specification for potential grid injection, use in μCHP, combustion in a natural gas boiler or other valorisation routes proposed by stakeholders. Once safety of the system is ensured, the system will be emptied and transported in a container for final integration in Demo 1 in operational environment at pre-commercial scale. The biogas conversion system will be initially dimensioned for the renewable energy recovery of 2600 kWh/y from biogas.

Solution S7B: After separation of the un-segregated wastewater in Demo 3, the solid fraction and grinded blackwater can be mixed and used for production of biogas and compost using a dry anaerobic digester. Goals foreseen by these solutions include the minimum recovery >95% food waste and >95% organic matter from solid fraction of wastewater for production of renewable energy from biogas (linked to S8) and compost (linked to S7c) at home level. The system will be adapted for biogas and compost production from blackwater or manure to the new feed. To make the existing system to work autonomously, some modifications like a feed slide need to take place. The sludge at the bottom of the anaerobic digester can be emptied regularly (once every 6 months), to produce high-quality compost.

Solution S7C: The generated biogas itself can be cleaned by using the absorption solution for increase of CH4 content and stored in inflatable and impermeable fabrics. This energy storage can be further used for potential grid injection, use in μCHP, or combustion in a natural gas boiler and can support the nearly zero energy building or even passive house claim to reach full autonomy even in winter times (December-February), when heating systems are mostly needed and sun heating will not be easily available.